This has been an excellent thread; any and all newbies should take heed and probably read it twice.
To all these comments I would only add that listening is a skill, developed over time and learning to identify the small changes in sound that happen after repositioning speakers is a good way to train your ears.
It helps me to be relaxed and in the right frame of mind. Patience is essential here because depending on the room and speaker combination very, very small adjustments in placement and toe-in will yield a noticeable change in response.
In my room it took a long time to strike the right balance between imaging and bass response, but after weeks and months the end result was satisfying.